A team of doctors will today accuse Hollywood of irresponsibility over its portrayal of sex and drugs after a review of some of the biggest blockbusters from the last 20 years showed that only one movie made reference to a condom.

None of the top 200 films promoted safe sex, and nobody ended up with an unwanted pregnancy or any infection. The doctors, writing in the Journal of the Royal Society of Medicine, say filmmakers should reflect the real consequences of unsafe sex and illicit drug use in their work.

"The movie industry influences the perception of billions of people around the world," said Hasantha Gunasekera from the school of public health at Sydney University. "With globalisation and the growth of home-based media technologies, movies are more accessible to a wider audience and there is convincing evidence that the entertainment media influences behaviour."

Dr Gunasekera and his two co-authors, Simon Chapman and Sharon Campbell, studied the top 200 movies of all time, as listed on the Internet Movie Database in March 2004. The researchers excluded any movie filmed before 1983, the pre-HIV era.

They also excluded animated features, those not about humans and any films rated acceptable for children. That left 87 films, in which there were 53 episodes of sex. Only once in those sex scenes did a condom feature, and that was a reference to birth control, they say. In 98% of sexual episodes, which could have resulted in pregnancy, no form of birth control was used or suggested.

There were no suggestions of any untoward consequences of unprotected sex, such as unwanted pregnancies, HIV or other sexually transmitted diseases. The doctors also looked at drug, alcohol and tobacco use in the films.

In 68%, people smoked and in 32% they got drunk. In only 8% was cannabis used and in 7% people took other non-injecting drugs. The researchers say the portrayal tended to be positive and without negative consequences. "The study showed there were no references to important consequences of unsafe sex such as HIV transmission, spread of STDs or unwanted pregnancy," said Dr Gunasekera. "The social norm being presented in movies is concerning, given the HIV and illicit drug pandemics in developing and industrialised countries. "The motion picture industry should be encouraged to depict safer sex practices and the real consequences of unprotected sex and illicit drug use."

The paper points out that 40 million people in the world are living with HIV/Aids, according to the World Health Organisation. "Addressing this problem in part requires population behaviour change relating to unsafe sexual practices and injected drug use," it says. "Observation of influential role models and the consequences of their actions affects our behaviour." Bottom of the league came Basic Instinct (1992), American Pie (2001) and the Bond film Die Another Day (2002).

Basic Instinct has six episodes of sex with no condoms used, no birth control and no public health consequences. American Pie has seven sex scenes, all involving new partners with no condoms or birth control measures. The "only consequences were social embarrassment", the report says. Die Another Day has three sex episodes, all with new partners, "no condoms, no birth control, no consequences at all".